The ProStaff 5 16-48x60 Spotting Scope from Nikon has a Porro prism design with fully multi-coated optics. A large magnification zoom of 16-48x allows a wider field scan followed by progressive magnification of finer details. The 60mm objective lens transmits enough light to make this spotting scope usable in the low-light periods of dawn and twilight. The angled eyepiece allows longer stress-free viewing sessions with a more comfortable view of targets near the zenith. There is a built-in sliding sunshade for protection from excessive glare or raindrops on the objective. The housing is fully O-ring sealed and purged with nitrogen to ensure all-weather performance. Regardless of the weather conditions, the field of view will be sparkling clear and the optic's internal mechanism will be well protected from the negative effects of moisture and atmospheric residue. Waterproof to 3.3 feet for up to 10 minutes, this fieldscope is suitable for all types of outdoor activities in any kind of weather. Backed up by Nikon's "No-Fault" repair/replacement lifetime warranty regardless of what happens to the scope—even from your own negligence—Nikon will repair or replace (at their option) this extremely well-built and durable fieldscope.